#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <bitset>
#include <utility>
using namespace std;

#define mm(a, n) memset(a, n, sizeof a)
#define mk(a, b) make_pair(a, b)

const double eps = 1e-6;
const int INF = 0x3f3f3f3f;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;
typedef pair<double, double> PDD;
typedef pair<LL, LL> PLL;
typedef pair<int, LL> PIL;

inline void quickread() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
}

int n, m, r, c;

inline void solution() {
    cin >> n >> m >> r >> c;
    char g[n + 1][m + 1];
    bool exits = false;
    for (int i = 1; i <= n; i ++ ) {
        for (int j = 1; j <= m; j ++ ) {
            cin >> g[i][j];
            if (g[i][j] == 'B') exits = true;
        }
    }
    if (!exits) cout << -1 << endl;
    else if (g[r][c] == 'B') cout << 0 << endl;
    else {
        exits = false;
        for (int i = 1; i <= n; i ++ ) 
            if (g[i][c] == 'B') 
                exits = true;
        for (int j = 1; j <= m; j ++ ) 
            if (g[r][j] == 'B')
                exits = true;
        if (exits) cout << 1 << endl;
        else cout << 2 << endl;
    }
}

int main() {
    freopen("input.txt", "r", stdin);
    quickread();
    int T;
    cin >> T;
    while (T -- ) {
       solution();
    }
    return 0;
}